docs: def dnet(dd, dm, zhm, xmm, xm):
      '''
  /*       TURBOPAUSE CORRECTION FOR MSIS MODELS
   *        Root mean density
   *         DD - diffusive density
   *         DM - full mixed density
   *         ZHM - transition scale length
   *         XMM - full mixed molecular weight
   *         XM  - species molecular weight
   *         DNET - combined density
   */
   '''
      a  = zhm / (xmm-xm)
      if( not((dm>0) and (dd>0))): # pragma: no cover
          if((dd==0) and (dm==0)):
              dd=1
          if(dm==0):
              return dd
          if(dd==0):
              return dm
  
      ylog = a * log(dm/dd)
      if(ylog < -10.0):
          return dd
      if(ylog>10.0): # pragma: no cover
          return dm
      a = dd*pow((1.0 + exp(ylog)),(1.0/a))
      return a